servicing instructions and illustrated · pdf file1 nlt-201 maincase 1 2 nmt-202 bearing...

© Copyright Hewland Engineering Limited 1999-2010

SERVICING INSTRUCTIONS AND ILLUSTRATED

PARTS LIST FOR HEWLAND NLT GEARBOXES

HEWLAND ENGINEERING LTD

WALTHAM ROAD, WHITE WALTHAM,

Last Updated: 24/09/2012

MAIDENHEAD, BERKSHIRE,

SL6 3LR, ENGLAND


CONTENTS :-

page page

Technical specification 4 NLT-212 adjustable diff 16

General notes 5 Differential Options 17-24

Differential bearing preload 6 Illustrated Parts List 25

Pinion shaft mounting 8 Tripod assembly 36

Pinion shaft bearing preload 9 Installation Drawings 39-41

Crownwheel backlash setting 10 Gearbox Tooling 42

Sequential barrel setting 11 General Technical Bulletins 43

Gearbox assembly 12-13 Oil system layout 45

Changing gear ratios 14 Manual History 48

Powerflow differential 15


ILLUSTRATIONS :-

page page

fig.1 Differential Bearing Preload 6 fig.14 Layshaft Assembly 30

fig.2 Differential Settings 7 fig.15 Pinion Shaft Assembly 32

fig.3 Pinion-shaft Setting 8 fig.16 Selector Assembly 34

fig.4 Pinion shaft Bearing Preload 9 fig.17 Tripod assembly 36

fig.5 Crownwheel Setting 10 fig.18 Installation Drawing 39

fig.6 Sequential Barrel Setting 11 fig.19 Installation Details 41

fig.7 Powerflow Diff Assembly 15 fig.20 Gearbox Tooling 42

fig.8-11Differential Assembly’s 17-24 fig.21 Oil System Layout 45

fig.12 Differential Subsidiary Parts 26


fig.13 Casing and Associated Parts 28

TECHNICAL SPECIFICATION

The NLT gearbox is a transaxle unit, designed for mid-engined, rear wheel drive cars. The unit is produced with six

forward gears, reverse, and a powerflow differential.

The gear selection mechanism is sequential, with a separate, mechanically interlocked reverse engagement mechanism.

The drive is taken from the engine via the clutch shaft, which turns input and pinion gears to drive the final transmission

assembly.

Gear changing is effected through non-synchronising face dogs. An extensive range of gear ratios provides a wide

range of gearing requirements. The gear ratios and differential assembly can easily be changed without removing the

gearbox from the vehicle.

Heat treated nickel chrome steel is used to manufacture all gears and shafts. The selector forks are also steel.

Lubrication is by splash or optional internal pump with distribution circuit, and the oil is retained by lipped oil seals.

In general configuration, the NLT-200 is a high tech racing transaxle unit which achieves the maximum effective use of

power, in conjunction with extremely stiff integral rear suspension mountings.

weight (AL) 148 lbs (67 Kg) 1st to 6th gear ratios from 3.0:1 to .857:1

oil type SAE 80 or 90 final drive ratio 9/35 & 10/31

oil quantity 7.875 pints (4.5 litres) clutch shaft made to customer's requirements

max. torque 500 lbs.ft (678 Nm) Pinion shaft nut tightening torque = 120 lbs.ft (163 Nm)

Crownwheel bolts = 75 lbs.ft (100 Nm)


GENERAL NOTES :-

a/ Read these instructions carefully and with reference to the illustrations.

b/ Before dismantling the gearbox, see that a clean tray is available, in which to place the parts.

c/ Thoroughly clean and inspect all parts before reassembly. Discard any worn or damaged components and replace with new ones.

d/ Use only genuine Hewland parts as replacements. These are manufactured in our workshops to the fine tolerances necessary and

are rigorously inspected.

e/ Always ensure that locknuts, and oil seals are in good condition when reassembling.

f/ All studs and screws must be Loctited or wirelocked in position, unless stated otherwise

g/ Bearing Replacement :-

Bearings can only be removed or renewed if the casings have been warmed in an oven, or with a blowlamp. In the latter case,

keep the blowlamp moving while heating the casing.

Note: Do not overheat. Test with a spot of water which will bounce off at the correct temperature.

Once a casing is heated, all bearings should be pressed into their respective seatings without delay, thus eliminating the need to

reheat. At the correct temperature, fitting the bearings should present no difficulty.

During cooling, or when the casings have cooled, it is advisable to once more lightly press the bearings to ensure that they are

correctly seated.

h/ Oil:

Fill the gearbox through the plug hole on top of the maincase. The oil will find it's own level within the gearbox.

Note: Too much oil will not directly cause any harm, but is undesirable as it may induce power loss and overheating of internals.


DIFFERENTIAL BEARING PRELOAD Requires special tools No. SK-119-FGC & SK-615

Assemble the differential case (57) and end cap (58), and bolt the

crownwheel (56) to it. Fit the differential unit into the maincase (1)

using dummy bearings SK-119-FGC and SK-615, and fit the

sideplate (3). Adjust the shims (103) & (133) if necessary, to

achieve 4 - 6 lbs.ft of bearing preload torque (to turn the diff

assembly in it’s bearings when oiled).

The table below is to inform you of which sideplate spacers should

be used with which crownwheel when mounted on a DGC

differential. The reason that there are two sets of spacers, is that the

crownwheels have different mounting distances.

FIGURE 1

Dummy bear-

ing SK-119-

Item 103

Item 91

Item 90

Dummy

bear-

Item 133

CROWNWHEEL & PINION RATIO

DGC-212 & DGC-212-S

MAINCASE BEARING SPACER SIDEPLATE BEARING SPACER

10:31 NLT-206-2 NLT-205-2

10:35 NMT-205-2A NLT-205-2A

9:35 NMT-205-2A NLT-205-2A

CROWNWHEEL & PINION RATIO

ADJUSTABLE DIFFS & DGCN-212 & DGCN-212-S

MAINCASE BEARING SPACER SIDEPLATE BEARING SPACER

10:31 NLT-205-2B NLT-205-2

10:35 FGC-206-2C NLT-205-2A

9:35 FGC-206-2C NLT-205-2A


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6

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8

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8

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85

10

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12

21

80

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4

25

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30

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8

33

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6

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37

60

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8

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50

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67

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83

30

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100

30

12

fig. 2


WITH FEELER GUAGES

SETTING TOOL:-

SK-1470-B

SHIM:-

NMT-223-1

SETTING TOOL:-

SK-1470-A

SKF 32209

MEASURE SETTING DISTANCE

fig. 3

PINION SETTING Requires special tool No.SK-1470-A & SK-1913

Press the pinion head bearing inner (37) onto the

pinion shaft (4). Fit the bearing housing (37) and

shims (40) into the maincase. Assemble the pinion

shaft into the maincase (1), then fit the spacer plate

(134) and bearing carrier (2). Tighten the pinion shaft

nut (111) onto the pinion shaft until the pinion shaft

requires 12-15 lbs.ins to turn it in it's bearings

(equivalent to a tangential force of 9.5-12 lbs at the

outside diameter of tool SK-1913)

Fit tool SK-1470-A into the maincase diff bearing

bore, and use feeler gauges to measure the gap

between the tool and the pinion front face. This

clearance should comply with the dimension

indicated on the pinion shaft label (also stamped on

the front face of the pinion shaft), and can be

adjusted by adding or removing shims (40) from

behind the pinion head bearing housing (37).

Alternatively, the pinion mounting distance can be

measured with a height gauge, and set to the

dimension on the pinion shaft label.

Note: It is not correct practice to replace a pinion

shaft without measuring the setting distance, even if

the old and new shafts have the same calibration.

SK-1913


PINION BEARING PRELOAD Requires special tool No.SK-1913

Having installed the correct pinion shaft

bearing shims, remove the bearing carrier

(2). Add the 6th gear inner track (14) and

hubs (20,33,143) to the pinion shaft, and

replace the bearing carrier. The thickness of

the inner track (14) should be adjusted, by

grinding the bearing side, to give a bearing

preload torque of 12-15 lbs.ins when oiled

(measure torque as when setting pinion

shaft, using tool SK-1913).

fig. 4

It is essential that the pinion bearing preload is checked and adjusted if any of the pinion shaft components are replaced, with the exception of the locknut and locking ring. Fitting a longer six gear inner track (14) will decrease the pinion bearing preload, whereas shortening the six gear inner track (14) will increase the pinion bearing preload.

GRIND INNER TRACK

TO ACHIEVE CORRECT

BEARING PRELOAD

SETTING TOOL:-

SK-1470-B

SKF 32209

SK-1913

fig. 4


CROWNWHEEL & PINION BACKLASH SETTING Requires special tool No. SK-1913

With the pinion shaft correctly fitted, and the correct diff

bearing shims ascertained, the actual backlash can be

measured by means of a dial test indicator against the

notch in the outside diameter of tool SK-1913. Be sure to

take at least 6 backlash readings, turning the crownwheel

30-45 degrees between each reading (this is to ensure

that any variation due to manufacturing tolerances are

taken account of.

The correct backlash figure should be taken from the

card supplied with the gears. If the measured backlash is

incorrect, rectify it by removing some shims (103 or

133) from behind one diff bearing, and inserting the

equivalent amount of shim behind the other, thus moving

the diff across in the maincase. Do not add or discard

any shims at this stage, as to do so would affect the diff

bearing preload.

Once the correct backlash has been achieved, replace the

dummy bearings with bearings (83,118) and confirm that

the backlash is correct.

Note: Dummy are used so that it is easy to change the shims

during the setting procedures. Before fitting the actual diff

bearings, it is important compare thier width with that of the

dummy bearings and compensate the shims accordingly for any

difference.

fig. 5


CLEARANCE

FIXTURE:-

SK-1658

SKF 32209

61806

618/8

DOG FACE

fig. 6

SEQUENTIAL BARREL SETTING - Requires special tool No.SK-1658

a/ Assemble the barrel (15), spacer (26), bearing retaining plate (25),

bearing (27), and nut (29). Heat the bearing carrier (2), slide the barrel

assembly into the bearing carrier, and secure using screws (12).

b/ Place the roller (24) onto the detent plunger (21), and insert them into

the bearing carrier (2). Add the detent spring (22), bonded seal (115),

and detent plug (23).

c/ Slide the selector forks (17) over the barrel (15), and secure using

selector pins (18). For final assembly, Loctite the pins (18) into the forks

(17).

d/ Stack the pinion gears (170), hubs (33,20), clutch rings (19) and 6th gear

inner track (14) in place in the bearing carrier (2), add the spacer plate

(134), and slide the whole thing onto the dummy shaft of fixture SK-

1658.

e/ Tighten the pinion shaft nut (111) onto the end of the pinion shaft,

ensuring that the disc spring on the fixture preloads the bearings.

f/ Rotate the barrel to engage first gear. Measure and record the gap

between the dogfaces of third through sixth gears. Engage third gear and

repeat the measurement for first and second dogfaces. It is important

that these dimensions are not taken when the barrel is in the neutral

position.

First, third and fifth gear dog gap measurements will be similar (as will

second, fourth and sixth). Any difference between the odd & even gear

measurements must be corrected by replacing the barrel spacer (26) with

one of the correct thickness.

Note: It is not possible (or necessary) to individually adjust each fork.


GEARBOX - ASSEMBLY

a/ It is assumed that all bearings, oil seals, studs, oil jets, and dowels are already fitted into casing. (see page 5).

b/ Assemble the oil pump components (if required). Heat the maincase, and drop the pump into position. Secure with screws , and add the drive

gear and circlip.

c/ Place the reverse idler gear (104), bearing (106), and thrust washers (107) in position in the bearing carrier, and slide the spigot (105) into

position. Secure with screw (12).

d/ Assemble the selector rack (75), washers (76), spring (77), and circlip (78), and slide into the maincase. Secure with the selector rack stop

(80).

Note: Check the gear linkage return spring length regularly (item 77). This spring has a finite life and will weaken with use. A new spring has

a free height of 1.450”. It is also adviseable never to re-use the circlip (78).

e/ Assemble the drum (8), bearing (28), pin (10), retaining plate (11), barrel driver (13), and shifter spindle (7). Pin (10) must be fitted into

“Hole A” of the drum (8), Assemble the drum shifter (6), guide plate (9), pawls (64), springs (63), and plungers (62), and slide into

engagement with the drum assembly. Push the complete assembly into it's location in the maincase, ensuring correct location with the selector

rack teeth.

f/ Assemble the selector input shaft (70), bearing (68), seal (71), spacer (72), quadrant gear (73) and circlip (112) into their housing (66). Slide

the whole assembly into the maincase, ensuring correct engagement with the selector rack (75).

g/ Build the selector barrel parts into the bearing carrier as described in the section 'Sequential Barrel Setting'.

h/ Fit the pinion shaft as described previously.

i/ Hold the reverse selector fork (31), with reverse pinion gear (30), in position in the bearing carrier (2). Slide the reverse selector shaft (110)

into place and secure with screw (176).


j/ With the bearing carrier face up, add the layshaft (50), input gears (170), spacers (45), disc spring (44), and bearing inner track

(43,138). Stack the reverse hub (33), hubs (20), mainshaft bearing inner track (143), pinion gears (170), bearings (120), clutch

rings (19), and 6th gear inner track (14) into position in the bearing carrier (2). When doing this, the spacer plate (134), bearing

support plate (135), bearings (154,155) and anti rotational plates (136) with screws (137) should also be added to the assembly.

Once this is done slide the dummy pinion shaft through from the bearing carrier end.

k/ Locating the tip of the dummy pinion shaft into the end of the pinion shaft, slide the completed gear cluster assembly into the

maincase to engage the pinion shaft and layshaft bearing. Whilst locating the gear cluster, lightly operate the selector rack (75)

to ensure correct location of the barrel and driver. Tighten the pinion shaft nut using tool No. SK-1452

l/ Fit the rear cover (36) using nuts (49), and dowels (162).

m/ Fit the clutch spigot bearing (97) and seal (98) into their housing (99) and secure with circlip (101). Slide the housing assembly

onto the clutch shaft (96) and secure with circlip (102). Fit the o'ring seal (100) onto the housing and slide the assembly into the

maincase to engage the layshaft (50). Fix the housing in place using screws (124).

Note : If the oil pump is fitted, the diff assembly must be removed from the maincase to allow the clutch shaft to be fitted (or

removed).

n/ Fit magnetic plug (114) and washer (115) to maincase.


CHANGING GEAR RATIOS

a/ With a drip tray placed beneath the gearbox, remove the drain plug (114) and drain the oil.

b/ Disconnect the reverse gear linkage from the gearbox.

c/ Remove the rear cover (36).

c/ Remove the M8 nuts (48) securing the bearing carrier (2), and slide it out of the maincase, complete with the gear cluster. It may

be necessary to tap lightly on the lugs provided to break the seal. Use a soft hammer for this purpose, never use a screwdriver to

lever between joint faces as this may damage the faces and impair the seal efficiency when reassembled. Take care not to drop

any of the pinion shaft components as they won't be fully supported at this time. The dummy shaft from SK-1658 can be used to

prevent the pinion shaft components from falling by inserting it into the rear end of the pinion shaft and sliding the loose parts

onto it.

d/ Remove the pinion gears (170), hubs (20), clutch rings (19) and bearing support plate (135). Slide the input gears (170), and

spacers (45) from the layshaft (50), then withdraw the layshaft from the bearing carrier.

e/ Replace the gears with the required ratios. Gears are supplied in matched pairs, one for the mainshaft and one for the layshaft.

Each gear is marked with two sets of numbers. The first of these indicates the number of teeth on the layshaft gear, while the

second figure signifies the number of teeth on the mainshaft gear which mates with it. Both gears of each pair are marked in an

identical manner. It is essential that gears are correctly paired to these numbers.

Note: On all first gears, and some second gears, the gear teeth are machined integral with the layshaft. In such cases, therefore, if

a first (or second) gear ratio change is required, the layshaft itself must be changed.

f/ Whilst changing ratios it is advisable, as a matter of course, to wash and inspect all components which are to be used again

before refitting. Check for wear and cracks, particularly to the clutch rings. Also examine the selector forks for heavy or uneven

wear.

g/ Reassembly is the reverse of disassembly. Take care, when refitting the gear cluster into the maincase, to ensure location of the

layshaft into it's bearing, and of the selector barrel (15) it's driver (13). Assembly of the pinion shaft components is made easier

by use of the dummy shaft as described previously.


POWERFLOW DIFFERENTIAL

This powerflow differential unit is designed with versatility as it's major asset. Many factors will contribute to the settings required. A car with

good traction and low power, may require a completely different arrangement to that of a car with poor traction and high power.

There are 10 friction plates within the unit (4 (87) splined to the diff casing (57), and 6 (88) splined to the side bevel gears(84). Slip limiting is

dependant on the friction resistance between these plates, and is affected by clamping the plates together.. Four factors contribute to the total

friction torque between the plates :-

3/ The second adjustable factor is

how tightly the plate stack is

compressed on assembly (known

as static preload). Included in the

plate stack is a preload spacer

(89). The preload torque is

measured between the side bevel

gears, by holding one side bevel

gear (84) stationary, and

measuring the torque required to

turn the other using tool SK-838-

T. When the diff is assembled, the

preload torque must be at least 10

lbs.ft, but can be much greater if

required. New plates ‘run in’ so a

higher preload is advised than

with used plates.

4/ The final adjustment is simply to

re-order the plate stack so as to

change the number of relatively

rotating faces. The diagram shows

the stack setup with the maximum

12 working faces. Standard stack

may be shuffled to give as few as

2 working faces.

1/ The side bevel gears (84) thrust

apart to clamp the plates as they

transmit the driving power. This

is a feature of the gear geometry,

and is not adjustable.

2/ The ramp angles cut on the side

ring gears (85) have an effect on

how much of the transmitted

torque is converted into sideways

(clamping) force onto the plates.

For example, on the drive side

ramp, 45 degrees transmits less

sideways force than 30 degrees.

Likewise on the coast side ramp,

an 80 degree angle will transmit

little or no clamping force onto

the plates, whereas a 45 degree

angle will transmit a much

greater force. Side ring gears

(85) are available with many

different drive/coast ramp angle

combinations.

FIGURE. 7


POWERFLOW DIFFERENTIAL ADJUSTMENT

The NLT-212 has the advantage of allowing external preload ad-

justment by the turning of a worm screw.

To adjust the preload of the differential, insert tool SK-1623 into

the worm and turn anti-clockwise to compress the spring to in-

crease the preload. Turn the worm clockwise to decompress the

spring and decrease preload.

The maximum preload that can be wound onto the differential

whilst using 12 friction surfaces is roughly 150lbsft. Fewer fric-

tion surfaces will not allow such a large preload figure.


DGC-212 Diff Assembly (superseded March 2010)

FIGURE 8

SEE TECHNICAL BULLETIN NLT-004

FOR MAINCASE REQUIREMENTS AND

DIFFERENTIAL BEARING PRELOAD

PAGE FOR MAINCASE AND SIDEPLATE

SPACERS


DGC-212 Diff Assembly, (March 2010 Onwards)

FIGURE 8a SEE TECHNICAL BULLETIN NLT-004




SPACERS


DGCN-212 Diff Assembly (August 2010 onwards)

FIGURE 8b






DGC-212-S Diff Assembly (superseded March 2010)

FIGURE 9





SPACERS


DGC-212-S Diff Assembly, (March 2010 Onwards)

FIGURE 9a





SPACERS


FIGURE 9b





SPACERS

DGCN-212-S Diff Assembly (August 2010 onwards)


NLT-212 Diff Assembly (superseded March 2009)

FIGURE 10

This differential was superseded by the differential shown on the next page.





SPACERS


NLT-212 Diff Assembly (Post March 2009)

FIGURE 11

This differential superseded the differential shown on the previous page. The differences are a new case, end cap, end cap screws and the addition of a sprung detent to the worm

THESE BOLTS MUST BE FITTED USING LOCTITE 648 RETAINER AND LOCKWIRE.





SPACERS


ILLUSTRATED PARTS LIST


FIGURE 12

83

118


ITEM No PART No DESCRIPTION QTY

3 NLT-205 SIDEPLATE 1

38 DG-219-1A CIRCLIP 2

54 VG-221-1 CROWNWHEEL BOLT 10

56 DGC-221-CW CROWNWHEEL 1

57 DIFF ASSEMBLY DIFFERENTIAL ASSEMBLY 1

65 OUTPUT FLANGE OUTPUT FLANGE 2

81 FGC-205-4 OIL SEAL 2

82 FGC-205-3 BALL BEARING 2

83 FGC-205-1 TAPER ROLLER BEARING 1

90** DIFF SPACER SIDE SPACER 1

91** DIFF SPACER MAIN SPACER 1

103 NLT-205-1A SHIM A/R

118 DGB-205-1 TAPER ROLLER BEARING 1

121 VG-201-9 SEAL STRIP A/R

133 FGC-206-1 SHIM A/R

** See page 6


FIGURE 13

135

161


CASINGS AND ASSOCIATED PARTS

ITEM No PART No DESCRIPTION QTY 1 NLT-201 MAINCASE 1 2 NMT-202 BEARING CARRIER 1 3 NLT-205 SIDEPLATE 1

12 HP-N-9006 SOCKET CAP SCREW 5

36 NMT-204 END COVER 1 48 STU-019 STUD 8 49 NUT-004 NUT 17 52 NUT-011 NUT 14 53 STU-017 STUD 14 93 FGB-201-8 BONDED SEAL 1

104 TE-237-1 REVERSE IDLER 1 105 TE-237-3 REVERSE IDLER SPIGOT 1 106 HC-237-2 NEEDLE ROLLER BEARING 1 107 HC-237-4 THRUST WASHER 2 113 NLT-201-1 OIL FILTER BUNG 1 114 HP-M-9004 MAGNETIC PLUG 1 115 HP-M-9042 SEALING WASHER 4 116 ORI-001 O-RING 3 117 OIL SPRAY OIL PLUG 1 121 VG-201-9 SEALING STRIP A/R

123 HP-M-9015 DOWEL 4

125 PLU-002 1/4 BSP HEX. HD. PLUG 3

126 WSH-017 1/4 BSP BONDED WASHER 3

127 SCR-159 BUTTON HEAD SCREW 1

128 HP-M-9062 SCREW 1

129 TE-201-4 BLANKING PLUG 1

ITEM No PART No DESCRIPTION QTY

130 HP-M-9037 BANJO BOLT 1

131 HP-M-9038 WASHER 2

132 HP-M-9039 BANJO BOLT 1

134 NLT-208-M/ALUM SPACER PLATE 1

135 NLT-208-A BEARING SUPPORT PLATE 1

136 TGTA-208-1 ANTI ROTATION PLATE 2

137 SCR-023 CSK SCREW 4

140 NLT-265-3 OIL PUMP FRONT COVER 1

144 STU-050 STUD 4

145 DOW-007 DOWEL 5

146 STU-062 STUD 1

147 DGB-265-7 OIL PUMP DRIVEN GEAR 1

148 FGB-265-5A CIRCLIP 1

149 FGB-265-2A OIL PUMP END COVER 1

150 FGB-265-2 OIL PUMP COVER 1

151 FGB-265-5 OIL PUMP ROTOR DRIVER 1

152 FGB-265-4 OIL PUMP ROTOR IDLER 1

153 SCR-076 CAP SCREW 4

154 BEA-041 ROLLER BEARING 1

155 TGT-201-6 ROLLER BEARING 1

156 SCR-019 LOW CAP SCREW 4

157 TE-266 OIL FILTER 1

161 STU-066 STUD 4

162 DOW-032 DOWEL 2

177 PLU-083 PLUG 1

178 ORI-024 ORING 1

179 WSH-053 DOWTY WASHER 1

* SEE TECHNICAL BULLETIN NLT-003 WITH REGARD TO DIFFERENTIALS AND MAINCASE REQUIREMENTS. NLT-201 is avail-able in magnesium or aluminium. Use NLT-201 for Aluminium and NLT-201-M for magnesium.

*

+

+ NLT-208 is available in magnesium or aluminium. Use NLT-208-ALUM for aluminium and NLT-208-M for magnesium.

** NLT-205 is available in magnesium or aluminium. Use NLT-205-A for Aluminium and NLT-205-M for magnesium.

**

ITEM NUMBERS 134 AND 135 CAN BE EXCHANGED AS A PAIR FOR SK-2428-A (NLT SPACER PLATE) AND SK-2428-B (NLT BEARING SUPPORT PLATE). THESE PARTS ARE NOT INTERCHANGEABLE.


ITEM No PART No DESCRIPTION QTY 42 BEA-093 ROLLER BEARING 1

43 NLT-234-2 INNER TRACK 1 44 105-234-8 SPRING WASHER 1 45 TGT-234-8 LAYSHAFT SPACER 2 46 DGN-RATIO-STD GEAR ASSEMBLY 5/4

47 TGT-234-8A SPACER 1

50 NLT-234-LS LAYSHAFT 1 51 BEA-001 ROLLER BEARING 1 96 NMT-239-1 CLUTCH SHAFT 1

97 DGB-244-12 BALL BEARING 1

98 FT-244-11 OIL SEAL 1

99 DGB-244 CLUTCH SHAFT BRG. HOUSING 1

100 DGB-244-14 ‘O’ RING 1

101 DGB-244-10 CIRCLIP 1

102 DGB-239-0 CIRCLIP 1

124 VG-244-13 CAP SCREW 6

138 NLT-234-1 LATSHAFT BRG. INNER TRACK 1

141 TGT-244-1 WIRE CLIP 1

142 NLT-265-9 MUFF COUPLING/PUMP DRIVER 1

50 NLT-234-Q ALTERNATIVE NON INTEGRAL LAYSHAFT

IF USED THEN REPLACE TGT-234-8A

(SPACER) WITH DGN-235-2 (RATIO)

1

46 TGT-RATIO-HUB LOWER SECOND GEAR RATIOS CAN BE A

HUBBED TYPE FOR INCREASED STRENGTH

0/1

LAYSHAFT ASSEMBLY


FIGURE 15


ITEM No PART No DESCRIPTION QTY 4 NLT-221-P PINION SHAFT 1 14 NLT-221-1 INNER TRACK 1 19 DGB-232-S CLUTCH RING 3

20 TGT-227 HUB 3

30 TE-231 REVERSE PINION GEAR 1 32 BEA-062 TAPER ROLLER BEARING 1 33 NLT-226 REVERSE HUB 1 34 NMT-230-1 LOCKING RING 1 35 FT-219-1A CIRCLIP 1 37 NLT-222 TAPER ROLLER BEARING 1 39 SCR-109 SOCKET CAP SCREW 5

40 NLT-223-2 SHIM 1 111 NLT-230 NUT 1

120 TGT-226-1 NEEDLE BEARING 6

143 TGTA-229-2 MAINSHAFT BRG INNER TRACK 1

158 WSH-036 PINION BEARING WASHER 5

170 DGN-RATIO-STD GEAR ASSEMBLY 6 177 SPA-072 SPACER 1

19 DGN-232 INVERTED DOG CLUTCH RING 3

20 DGN-227 INVERTED DOG HUB 3

PINION SHAFT ASSEMBLY

**

** **

**

** - Boxes built after February 2010 will have the inverted dog spec hubs and clutch rings. When selecting hubs and dog rings make sure that

the inverted dog or non inverted dog parts are selected and not a mixture. Both specs use the same gears.


FIGURE 16

173


ITEM No PART No DESCRIPTION QTY 5 BEA-035 NEEDLE ROLLER BEARING 1 6 TE-260-6A DRUM SHIFTER 1 7 TE-260-4 SHIFTER SPINDLE 1 8 105-260-4 DRUM 1 9 NMT-260-5 GUIDE PLATE 1

10 HP-M-7022 DOWEL 1 11 NMT-260-2 KEEP PLATE 1 12 HP-N-9006 SOCKET CAP SCREW 5 13 TE-260-1 BARREL DRIVER 1 15 NLT-260 BARREL 1 17 IGT-250 SELECTOR FORK 3 18 IGT-250-1 SELECTOR FORK PIN 3 21 102-260-4 DETENT PLUNGER 1

22 102-205-11 SPRING 1

23 TE-202-1 DETENT PLUG 1

24 BEA-059 ROLLER 1

25 NMT-202-1 BEARING RETAINING PLATE 1 26 TE-260-7 BARREL SPACER 1 27 BEA-037 BALL BEARING 1 28 HP-M-8008 BALL BEARING 1 29 TE-260-5 BARREL BOLT 1 31 TE-249 REVERSE SELECTOR FORK 1 60 TGTA-206-2 SELECTOR RACK STOP 1 61 WSH-013 BONDED SEAL 1 62 HP-M-7018 PLUNGER 2 63 HP-M-7018-A SPRING 2

SELECTOR ASSEMBLY

ITEM No PART No DESCRIPTION QTY 66 NMT-252-2 BEARING PLATE 1

67 LD-253-4 SOCKET COUNTERSUNK SCREW 4

68 BEA-051 BALL BEARING 1

70 NMT-252 SELECTOR INPUT SHAFT 1

71 HP-M-8012 OIL SEAL 1

72 NMT-252-3 SPACER 1

73 NMT-252-1 QUADRANT GEAR 1

74 BEA-052 BALL BEARING 1

75 NMT-260-3 SELECTOR RACK 1 76 102-260-11 WASHER 2 77 102-260-9 SPRING 1 78 102-260-8 CIRCLIP 1 79 WSH-010 BONDED SEAL 1 80 NMT-202-2 SELECTOR RACK STOP 1 92 SPR-011 COMPRESSION SPRING 1

94 WSH-018 1/2” PLAIN WASHER 1

95 HP-M-9034 1/4 BSP PLUG 2

108 BEA-038 BUSH 2

109 LIP-015 LIP SEAL 1

110 TE-246-1 REVERSE SELECTOR SHAFT 1

112 CIR-033 CIRCLIP 1

115 HP-M-9042 BONDED WASHER 4

121 VG-201-9 SEALING STRIP A/R

173 HP-M-7017 PAWL 2 176 SCR-046 SCREW 1

172 HC-202-8 PLUG 1


NLT-218-TRIPOD ASSEMBLY

FIGURE 17


Variable Parts


NLT-200-I Installation Drawing

FIGURE 18


NLT-200-I Installation Drawing


NLT-200-I Installation Details

FIGURE 19

7.859 199.6

7.859 199.6

3.5

14

8

9.2

6

NLT-218-TRIPOD

FGC-218-C

FGC-218-AT R/H

FGC-218-A R/H


Gearbox Tooling

FIGURE 20

NLT-212 requires tooling. See NLT-212 diff part list page for tools


10 April 2000

General Technical Bulletin No. 14

DGC Differential Bevel Gears

In line with Hewland Engineering’s constant quest to improve and develop its products, the DGC differential bevel gears have been redesigned to improve the tooth strength and smoothness of operation. In order to identify the new designs, all variations of the DGC gears cut to the revised specification will have a “D” suffix in the part number. e.g. DGC-213-6D DGC-213-5D On the new components there will also be a tool tip groove to indicate the new form, on the side bevels this will be on the o.d. of the core plate splines, on the planet bevels it will be on the front face, toe end of gear. It is recommended that that the “D” specification bevels are always run with a mating gear of the same specification. In extreme circumstances it may be possible to run “D” specification bevels with the older spec. bevels. The user must realise this is not condoned by Hewland Engineering. Note: If the new “D” spec. planet gears are run with the older spec DGC side bevel gears, they will have a reduced backlash/clearance figure. This may result in incorrect operation of the differential, as the preload will be applied across the bevel gear teeth and not the side ring gears/ramps, causing premature wear of the components. If “D” specification side bevel gears are run with older spec. DGC planet gears there will be an increase in the backlash/clearance, which may result in failure due to increased shock loads. Colin Reynolds

SEE NLT BULLETIN #002


NMT Technical Bulletin No.001

POSITION OF GEAR INDICATOR POTENTIOMETER


22 March 2004

NLT OIL SYSTEM LAYOUT

FIGURE 21

SEE HYD-041 FOR OIL SYSTEM

PIPEWORK KIT REFERENCES.

(OIL COOLERS ARE NOT INCLUDED.)


Technical Bulletin NLT Gearbox. Issued: 14/10/2009 Bulletin: NLT-002 Re: DGC Bevel gears Author: Jason Allen

As part of Hewland Engineering’s ongoing product development, the DGC bevel gears have been redesigned to enable compatibility with our in house machinery. The change to the design has no affect on performance or life of the parts. In order to identify the new designs, all variations of the DGC gears cut to the revised specification will have a “AH” suffix in the part number. e.g. DGC-213-6AH DGC-213-5AH


Technical Bulletin NLT Gearbox. Issued: 23/08/2010 Bulletin: NLT-004 Re: NLT-201 maincase Author: Charles Ingram

Pre August 2010, the NLT-201 maincase was either machined to accept a DGC-212 non preload adjustable differential (Figure A) OR machined to accept an NLT-212 preload adjustable differen-tial (Figure B). Neither machining spec would accept both differ-entials. The DGC-212 has now been strengthened and adapted to retrofit an NLT-212, creating the DGCN-212, and therefore all NLT-201 maincases machined after August 2010 will accept the NLT-212 adjustable differential AND the DGCN-212 (Figure B). If you have a maincase as shown in Figure A AND 1) You want a new DGC-212 differential, you require TLT-213

diff case and NLT-214-B end cap 2) You want to replace the maincase, you require TLT-213 diff

case and NLT-214-C end cap 3) You want an NLT-212 differential, you need to buy a main-

case or machine your existing maincase as shown in Figure B.

The DGCN-212, which has the NLT-213-C end cap, is inter-changeable with any NLT-212 differential. For diff details please refer to the NLT manual

Figure A: Only suitable for DGC-212 differentials

Figure B: Suitable for all differen-tials except DGC-212 differentials.

This technical bulletin supersedes NLT-003


Manual Modification History

DATE MODIFICATION 28/06/2011 Page 28– Items 135 and 161 labelled on Fig. 13 Page 29– Note added re. substituting Items 134 and 135 21/10/2011 Page 28 & 29 - Item 127 updated and item 179 added 15/11/2011 Page 32 - Image updated to include item 158 10/07/2012 Page 36 - Figure 17 updated to show latest parts 24/09/2012 Page 35 - Item 21 Part number and description amended

servicing instructions and illustrated · pdf file1 nlt-201 maincase 1 2 nmt-202 bearing...

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